Thank you for making this video Larry! I am of course subscribed with notifications turned on and thumbs up! 73 W3GUY Side note on this one, it would be awesome if you could show stacking three or more toroids in a high powered low loss configuration that you would personally recommend for 160 through 10 m.
Fantastic Larry! Thank you! To evaluate power loss and heating in an RF transformer using these core materials, would a model of it in a RUSE block work similarly to what you have done here? I have a homebrew transformer wound on a small #61 binocular core at an antenna feedpoint to match the impedance to 50-ohm coax. (4T primary, 5T secondary, 14 MHz.) I'm only running 100W max and the temperature rise is barely detectable, but I have wondered how to evaluate a transformer like this for higher power.
DP, SimSmith will calculate the power dissipated in any component including a RUSE block or S parameter block etc. Underneath every component except the generator are 4 lines that are R, X, W, VI. The 3rd line will be displaying "left arrow W (power in W delivered to the component), "left arrow dBW (power in dBW delivered to the component), "up arrow W (power in W dissipated by the component), or "up arrow dBW (power in dBW dissipated by the component). Clicking on this space will toggle between the 4 power measurements and you want "up arrow W". Then your goal is to accurately model the transformer. This ideally should be done via measurements. I would then model the transformer in a S parameter block. This is probably more work than you might want to do. If that happens I would look for another way to achieve the same goal. I might take a high power dummy load and connect a high power tuner to it and adjust the tuner to give the correct impedance to the transformer you want to test and then drive the transformer under test into the tuner and measure how hot it gets. You may need a second tuner on the generator side of the transformer under test if the circuit does not give the transmitter a reasonable SWR. Finally you can just "wing it" by saying if it only gets barely warn at 100W then it will dissipate 5X more at 500W. You can do some measurements by winding the core as a plain inductor with few enough turns to guarantee it will get quite warm at low power. The drive power into it until it gets as warm as the real transformer you want to test and then increase the power 5X and see how hot it is. There are many ways to accomplish what you want to do. Larry, W0QE
Another great video. So for a typical 2:14 turn EFHW unun auto transformer using a single or double FT-240 core(s), most recommend either the 43 or 52 materials for 80m-10m. But it appears the 61 material is better for higher power applications than 43 for this application. Is that correct?
NO5X, Assuming that you want to have the exact same transformer with the 61 material vs the 43 material and are using the same size core(s) for both you will need to increase the number of turns for each winding in order for the inductance to be the same. The 61 material transformer will be operating at a lower flux level and should also have lower loss. Now if you raise the power the flux level will rise and you may also need to increase the wire gauge due to the increased current. The 61 material transformer may have more capacitance between the windings (more turns) which will need to be analyzed. You could also take a different approach and wind both transformers with the same number of turns and adjust the antenna length slightly to account for the decreased shunt inductance. I know you wanted a simple yes or no answer but it always is so easy. Does this help? Larry, W0QE
@@w0qe Absolutely it helps! What test equipment did you use to generate the 1500 watt signal at the 3 test frequencies? (I assume a ham radio + amp ?) How did you measure the temperature during testing? (thermocouple, RTD or Infared meter ?)
@@johntrites3387 I have a couple of ham radio amps that are capable of 1500W 100% duty cycle output. To measure temperature I usually paint a 1/4" diameter flat black paint dot on the object and use an infrared spot meter which has a 1/8" spot measuring area. This meter needs to be about 3/4" from the dot for the 2 led beams to converge. Larry
@@w0qe I think your setup for the 43, 61, and 31 materials all had 12 turns. In your test case, they would have different inductance values for a fixed 12 turns. And, these material cores with the same turns will be operating at the same flux density level regardless of the material type. So at 5:29 time, you show different power losses at 1.85, 7, and 28.5 MHz (frequencies setup at generator) I assume because of the measured "file(s)" loaded for each material type. What instrument did you use to make these toroidal core impedance measurements for each material? I assume a VNA. Which VNA? What frequency range? And, does each toroidal inductor material file include both resistive and reactive values over the frequency range? Are those 3 toroidal inductor material files available to duplicate your work?
Without looking at the files from 4 years ago I'm pretty sure I used an AIM4170 analyzer to make the measurements. Absolutely any measurements that I made included both the reactive and resistive part of the impedance over the frequency range. This video was from before I started to include the files on Dropbox but the files that I loaded into SimSmith show power loss due to the resistive part of the impedance. I could send you the files in a format that SimSmith can easily read. Larry, W0QE
Thank you for making this video and sharing it with us. I however am still new and at this point still lost. If you were designing and EFHW for 80 through 10 m and wanted to run full power, which material would you use that resulted in the lowest loss best performance? What about if you wanted to do 160 through 10 m? With all of your years experience, can you recommend any products that can be used as EFHW 80 through 10 or 160 through 10 at the full 1500 watts with the lowest loss and best performance in your opinion? I'm in this middle world where I don't see any products that claim continuous duty at 1500 watts for EFHW multiband, if there was something really excellent that you were aware of I would just as soon purchase, but if not I would like to build the best based on your guidance. Thoughts? 73 W3GUY
Ernest, The EFHW has almost a cult following but it is really nothing special and is easily modeled. At low power levels the ground connection is often an oversight as the current is very low. However that is not true at high power and a serious common mode choke in the coax will probably be needed or you will have RF in the shack unless you have a good ground at the antenna. Let's assume that you expect the load to be about 3k ohms mostly resistive you will need a transformer to step up the impedance from 50 ohms. The output voltage of the transformer will be ~2200Vrms or a little over 3000Vpk. This voltage is across the secondary winding of the transformer. It will not be a simple task to keep the power dissipated in the core low enough to not have the core overheat unless you have a lot of turns which will be problematic. Videos #80 thru #84 described these types of calculations. You are going to need multiple cores and not small ones. A VNA can measure the inductances of the transformer winding vs frequency and the core loss can be calculated. Temperature rise is your only concern as there are no modulation types in HF amateur radio that will cause the cores to saturate before they heat up to dangerous temperatures. I would probably start by building a lower power version of the transformer. I know this isn't the answer you want to hear I would suggest you start with a 2.4"OD #43 core and wind 2 transformers. Place them back to back and then use a tuner to match to a dummy load. You will need to match out the leakage inductance in order for the transmitter/amplifier to be happy. Good luck, 73, Larry, W0QE
@@w0qe Larry, this is exactly the answer I was looking for! I am currently watching many of your videos, so directing me to ones that will help certainly does help! Additionally to do it right I really did think I would need multiple large cores, but I would like to see and do the calculation and get it right. That was assuming that someone didn't have an over-the-counter product that already is designed for 1,500 w continuous, which so far I can't seem to find one, well not one that lists a true continuous power rating, I do see a vendor listing something called ICAS which appears to be some kind of intermittent power rating? Again, thank you very much for the detailed reply and I'm going to watch the videos for sure! And yes agreed it does have a cult like following, but mostly at low power levels compared to what I would like to do. This type of antenna lends itself very well to multiband at the current location where I live, and end-fed antenna is a simple method that will work with the yard I have. I have really been enjoying your videos and I do have a cheap VNA and have been playing around with it a lot lately for VSWR charts. I am only now learning the language of actual RF engineers like return loss and your videos are really helping. Thank you very much for the detailed reply if you think of anything else that might help, please let me know. 73 W3GUY Ernie
Ron, Because "G" is the component and MHz is the parameter of that component. SimSmith allows nearly every parameter to be swept which is part of the program's power. Does this help? Larry
Steven, I do have the files ans many more that I used in making the video. Without watching the video I don't know which files were in the video. Is there a particular file that you want? I can email it to you. Larry
Absolutely a fantastic Video! I love the power of SimSmith. I love your videos which really help me to learn.
Thanks Larry, I hope more people finds your fantastic channel.
great video! please keep uploading!
Great video, Larry. I am surprised your hands still work after winding all those cores with #12 wire!
Thank you for making this video Larry! I am of course subscribed with notifications turned on and thumbs up! 73 W3GUY
Side note on this one, it would be awesome if you could show stacking three or more toroids in a high powered low loss configuration that you would personally recommend for 160 through 10 m.
Fantastic Larry! Thank you! To evaluate power loss and heating in an RF transformer using these core materials, would a model of it in a RUSE block work similarly to what you have done here? I have a homebrew transformer wound on a small #61 binocular core at an antenna feedpoint to match the impedance to 50-ohm coax. (4T primary, 5T secondary, 14 MHz.) I'm only running 100W max and the temperature rise is barely detectable, but I have wondered how to evaluate a transformer like this for higher power.
DP,
SimSmith will calculate the power dissipated in any component including a RUSE block or S parameter block etc. Underneath every component except the generator are 4 lines that are R, X, W, VI. The 3rd line will be displaying "left arrow W (power in W delivered to the component), "left arrow dBW (power in dBW delivered to the component), "up arrow W (power in W dissipated by the component), or "up arrow dBW (power in dBW dissipated by the component). Clicking on this space will toggle between the 4 power measurements and you want "up arrow W". Then your goal is to accurately model the transformer. This ideally should be done via measurements. I would then model the transformer in a S parameter block. This is probably more work than you might want to do. If that happens I would look for another way to achieve the same goal. I might take a high power dummy load and connect a high power tuner to it and adjust the tuner to give the correct impedance to the transformer you want to test and then drive the transformer under test into the tuner and measure how hot it gets. You may need a second tuner on the generator side of the transformer under test if the circuit does not give the transmitter a reasonable SWR.
Finally you can just "wing it" by saying if it only gets barely warn at 100W then it will dissipate 5X more at 500W. You can do some measurements by winding the core as a plain inductor with few enough turns to guarantee it will get quite warm at low power. The drive power into it until it gets as warm as the real transformer you want to test and then increase the power 5X and see how hot it is.
There are many ways to accomplish what you want to do.
Larry, W0QE
How are we actullay importing the core materials characteristics into simsmith?
Another great video. So for a typical 2:14 turn EFHW unun auto transformer using a single or double FT-240 core(s), most recommend either the 43 or 52 materials for 80m-10m. But it appears the 61 material is better for higher power applications than 43 for this application. Is that correct?
NO5X,
Assuming that you want to have the exact same transformer with the 61 material vs the 43 material and are using the same size core(s) for both you will need to increase the number of turns for each winding in order for the inductance to be the same. The 61 material transformer will be operating at a lower flux level and should also have lower loss. Now if you raise the power the flux level will rise and you may also need to increase the wire gauge due to the increased current. The 61 material transformer may have more capacitance between the windings (more turns) which will need to be analyzed. You could also take a different approach and wind both transformers with the same number of turns and adjust the antenna length slightly to account for the decreased shunt inductance.
I know you wanted a simple yes or no answer but it always is so easy. Does this help?
Larry, W0QE
@@w0qe Absolutely it helps! What test equipment did you use to generate the 1500 watt signal at the 3 test frequencies? (I assume a ham radio + amp ?)
How did you measure the temperature during testing? (thermocouple, RTD or Infared meter ?)
@@johntrites3387 I have a couple of ham radio amps that are capable of 1500W 100% duty cycle output. To measure temperature I usually paint a 1/4" diameter flat black paint dot on the object and use an infrared spot meter which has a 1/8" spot measuring area. This meter needs to be about 3/4" from the dot for the 2 led beams to converge.
Larry
@@w0qe I think your setup for the 43, 61, and 31 materials all had 12 turns. In your test case, they would have different inductance values for a fixed 12 turns. And, these material cores with the same turns will be operating at the same flux density level regardless of the material type.
So at 5:29 time, you show different power losses at 1.85, 7, and 28.5 MHz (frequencies setup at generator) I assume because of the measured "file(s)" loaded for each material type.
What instrument did you use to make these toroidal core impedance measurements for each material? I assume a VNA. Which VNA? What frequency range?
And, does each toroidal inductor material file include both resistive and reactive values over the frequency range?
Are those 3 toroidal inductor material files available to duplicate your work?
Without looking at the files from 4 years ago I'm pretty sure I used an AIM4170 analyzer to make the measurements. Absolutely any measurements that I made included both the reactive and resistive part of the impedance over the frequency range. This video was from before I started to include the files on Dropbox but the files that I loaded into SimSmith show power loss due to the resistive part of the impedance. I could send you the files in a format that SimSmith can easily read.
Larry, W0QE
Thank you for making this video and sharing it with us. I however am still new and at this point still lost. If you were designing and EFHW for 80 through 10 m and wanted to run full power, which material would you use that resulted in the lowest loss best performance? What about if you wanted to do 160 through 10 m?
With all of your years experience, can you recommend any products that can be used as EFHW 80 through 10 or 160 through 10 at the full 1500 watts with the lowest loss and best performance in your opinion? I'm in this middle world where I don't see any products that claim continuous duty at 1500 watts for EFHW multiband, if there was something really excellent that you were aware of I would just as soon purchase, but if not I would like to build the best based on your guidance. Thoughts? 73 W3GUY
Ernest,
The EFHW has almost a cult following but it is really nothing special and is easily modeled. At low power levels the ground connection is often an oversight as the current is very low. However that is not true at high power and a serious common mode choke in the coax will probably be needed or you will have RF in the shack unless you have a good ground at the antenna.
Let's assume that you expect the load to be about 3k ohms mostly resistive you will need a transformer to step up the impedance from 50 ohms. The output voltage of the transformer will be ~2200Vrms or a little over 3000Vpk. This voltage is across the secondary winding of the transformer. It will not be a simple task to keep the power dissipated in the core low enough to not have the core overheat unless you have a lot of turns which will be problematic. Videos #80 thru #84 described these types of calculations. You are going to need multiple cores and not small ones. A VNA can measure the inductances of the transformer winding vs frequency and the core loss can be calculated. Temperature rise is your only concern as there are no modulation types in HF amateur radio that will cause the cores to saturate before they heat up to dangerous temperatures. I would probably start by building a lower power version of the transformer.
I know this isn't the answer you want to hear I would suggest you start with a 2.4"OD #43 core and wind 2 transformers. Place them back to back and then use a tuner to match to a dummy load. You will need to match out the leakage inductance in order for the transmitter/amplifier to be happy.
Good luck,
73, Larry, W0QE
@@w0qe Larry, this is exactly the answer I was looking for! I am currently watching many of your videos, so directing me to ones that will help certainly does help! Additionally to do it right I really did think I would need multiple large cores, but I would like to see and do the calculation and get it right. That was assuming that someone didn't have an over-the-counter product that already is designed for 1,500 w continuous, which so far I can't seem to find one, well not one that lists a true continuous power rating, I do see a vendor listing something called ICAS which appears to be some kind of intermittent power rating? Again, thank you very much for the detailed reply and I'm going to watch the videos for sure! And yes agreed it does have a cult like following, but mostly at low power levels compared to what I would like to do. This type of antenna lends itself very well to multiband at the current location where I live, and end-fed antenna is a simple method that will work with the yard I have. I have really been enjoying your videos and I do have a cheap VNA and have been playing around with it a lot lately for VSWR charts. I am only now learning the language of actual RF engineers like return loss and your videos are really helping. Thank you very much for the detailed reply if you think of anything else that might help, please let me know. 73 W3GUY Ernie
Why does "sim Smith" display "G.MHz" where I expect "MHz"? (bottom of chart)
Ron,
Because "G" is the component and MHz is the parameter of that component. SimSmith allows nearly every parameter to be swept which is part of the program's power. Does this help?
Larry
do you have the simsmith files available from this video?
Steven,
I do have the files ans many more that I used in making the video. Without watching the video I don't know which files were in the video. Is there a particular file that you want? I can email it to you.
Larry